Critical Heat Flux on a Horizontal Cylinder in an Upward Subcooled and Low-Quality Two-Phase Crossflow

An experimental investigation has been conducted to determine the low-velocity critical heat flux (CHF) behavior on a single horizontal tube in a subcooled and low-quality two-phase crossflow of R-113. Data were obtained over a range of velocities (up to 0.3 m/s), subcooling (0 to 14 K), and qualities (0 < x < +30 percent) at two pressures. There was a linear decrease in the CHF with increasing quality up to about 10 percent quality; then, due to a flow regime transition, the CHF remained relatively constant. A correlation has been developed which predicted well the subcooled and low-quality region CHF condition in the linearly decreasing portion of the curve. Data from the literature are also predicted well.